258
FXUS61 KPHI 302010
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
410 PM EDT Wed Jul 30 2025

.SYNOPSIS...
A slow moving cold front will push into the region beginning
late tonight and persist into Thursday night. The front is
expected to bring widespread showers and storms. High pressure
will then build in from the north through the weekend and
provide the area with below normal temperatures and much drier
air. These conditions will last into early next week. The next
weather-maker is then expected to arrive sometime next Tuesday
or Wednesday.

&&

.NEAR TERM /THROUGH THURSDAY/...
The Heat Advisory in effect for most of the area remains in
effect until 8 PM EDT.

A pattern-changing cold front will pass through the region
Thursday night, and a widespread flash flooding event is
expected Thursday afternoon and Thursday night.

Hot and humid conditions remain in place through this evening.
A weak cold front approaches from the west this evening, then
will get hung up over northern zones tonight through Thursday
morning. Scattered showers and thunderstorms, capable of locally
heavy rain and gusty winds, will impact areas mainly north of
I-78 through this evening. The Storm Prediction Center has a
Marginal Risk (1 out of 5) for severe weather through this
evening. Due to the heat and high dew points, SB CAPE values
range from 2000 to in excess of 3000 J/kg, with DCAPE values in
up to 1000 J/kg. While storm coverage is not expected to be
widespread, any thunderstorm that does develop will be capable
of locally damaging wind gusts.

Showers and thunderstorms mostly taper off this evening, though
lingering showers may continue over the Lehigh Valley, southern
Poconos, and far northwest New Jersey. Another warm and muggy
night is on tap for the area with lows generally in the 70s, and
possibly not much lower than 80 in Philadelphia.

With that front hanging north of the area on Thursday, winds
will take on more of an east to southeast flow. While wind
speeds will not be particularly high, it will be enough to allow
low level moisture to increase over the area, and surface dew
points will rise well into the 70s. Clouds will increase over
the area, and these clouds, along with showers developing in the
afternoon, should keep high temperatures from exceeding 90
degrees in most areas. While extremely uncomfortable despite
the lower temperatures generally in the 80s to low 90s in
Delmarva, max heat index values should fall below Heat Advisory
criteria, so will not issue any additional heat products at this
time.

Scattered showers and thunderstorms will continue to develop
across the Lehigh Valley, southern Poconos, and northwest New
Jersey Thursday morning. An H5 trough with strong shortwave
energy approaches in the afternoon, and surface low pressure
will develop southwest of the area, crossing Delmarva and
southern New Jersey in the evening ahead of the approaching
cold front. The cold front will work its way east Thursday
night, crossing most of the area by daybreak Friday.

Abundant tropical moisture will be in place, and then will
increase further in the afternoon and evening with surface dew
points well in the 70s. This will yield PWATs well in excess of
2 to 2.5 inches. Heavy rain will be the main threat. The Weather
Prediction Center has a Moderate Risk (3 out of 4) for most of
the urban corridor from around Newark to Philadelphia to
Wilmington and surrounding areas, and a Slight Risk (2 out of 4)
for the rest of the region. Models are indicating rainfall
amounts generally 2 to 4 inches in that Moderate Risk, with
localized amounts in excess of 6 inches. Rainfall rates could
also be in excess of 2 inches per hour. A Flood Watch is in
effect for southeast Pennsylvania, New Jersey, the eastern
shores of Maryland, and Delaware for Thursday afternoon through
Thursday night, with a highlighted focus on the urban corridor.
Make sure you have a way to receive any flash flood warnings on
Thursday, and remember not to drive around barricades.

The heaviest of the showers and thunderstorms will begin to
taper off after midnight from west to east, but lingering
showers and thunderstorms will be possible. Any extensive
flooding that does develop may not subside until sometime
Friday.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
With the cold front south of the forecast area, Friday will
feel a whole lot different then today and yesterday. High
temperatures will top out mainly in the 70s. Our far
northwestern zones will likely remain in the 60s. Maybe Delmarva
touches 80.

Along with the cool temperatures, precipitation and gusty
northeast will make for an unpleasant day compared to late July
standards.

Diffluence will remain in place aloft as Canadian high pressure
begins to build in from the north. This setup will result in
cloudy skies along with an unusually breezy northeast wind.
Lingering showers and drizzle can also be expected, especially
across the coastal plain. Northeast winds 10 to 20 mph with
gusts to near 30 mph are possible, maybe even 35 mph near the
coast.

Dewpoints in the 50s this weekend? Yes

Drier air will finally start to work into the area from the
north Friday night and especially by Saturday as high pressure
takes hold of the region. Lows Friday night will be 50s and 60s.
Highs Saturday will be near 80 degrees (low to mid 70s across
the southern Poconos). Dewpoints will be in the 50s, perhaps
even mixing out into the upper 40s in some spots.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The long term looks pretty benign with high pressure in play.
Any rain chance will hold off until sometime Tuesday or
Wednesday. More comfortable dewpoints will persist through
Sunday and even into Monday. They`ll tick up Tuesday and
Wednesday. Overnight lows through the period should hold in the
50s and 60s. Afternoon highs will remain below 90. This will
equate to below normal temperatures.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Rest of today...VFR. Low chance for a SHRA/TSRA to impact
KRDG/KABE/KTTN. Will carry VCTS at KRDG/KABE through late
afternoon. S-SW winds 5 to 10 kt. Low confidence on a SHRA/TSRA
passing directly over those northern terminals

Tonight...VFR. There is the potential for VSBY restrictions in
fog after 08Z. S-SW winds 5 to 10 kt, becoming LGT/VRB by 06Z.
Low confidence on fog formation late tonight.

Thursday...Any morning fog lifts and dissipates from 12Z-13Z.
VFR until 18Z, then sub-VFR in SHRA/TSRA. Potential for heavy
rain. SE to E winds 5 to 10 kt. Moderate confidence.

Outlook...

Friday...Sub-VFR conditions expected with both ceiling and
visibility restrictions. Gusty NE winds.

Friday night...Conditions improving to VFR.

Saturday through Monday...VFR conditions expected with no
significant weather.

&&

.MARINE...
Sub-Small Craft Advisory conditions through Thursday night.
South to southwest winds 10 to 15 kt tonight will become east to
southeast on Thursday and Thursday night, increasing to 15 to
20 kt Thursday night.

VSBY restrictions in showers and thunderstorms, along with
locally higher winds and waves, Thursday afternoon and Thursday
night. Heavy rain expected.

Outlook...

Friday and Friday night...SCA conditions expected. Gale force
wind gusts possible. Northeast winds 20-25 kts with gusts 30-35
kts. Scattered showers, storms, and drizzle.

Saturday and Saturday night...SCA conditions likely. Conditions
slowly improving north to south with decreasing winds and seas,
though seas near 5 feet will likely linger into the night.

Sunday...Conditions will fall below advisory criteria.

Monday...Sub-SCA conditions expected.

Rip Currents...

For Thursday, southerly winds around 5-10 mph will become east-
southeast in the afternoon. Breaking wave heights around 1-2
feet with a 1 foot southeast swell period around 8 seconds. As a
result, have maintained a LOW risk for the development of
dangerous rip currents at all beaches.

For Friday, northeast winds strengthen to around 15-25 mph.
Breaking wave heights will vary between 3-5 feet to the north and
2-4 feet to the south with a building northeasterly 5-7 foot swell
around 6-7 seconds. As a result, opted to go with a HIGH risk for
dangerous rip currents for Monmouth and Ocean County beaches where
winds/swell are more perpendicular to shore, with a MODERATE risk
elsewhere where winds/swell are more shore parallel. A rip current
statement will likely be needed in the future updates.

For specific beach forecasts, visit weather.gov/beach/phi

&&

.CLIMATE...
Several days of high heat commenced Monday and will continue
through today. No records were reached Monday. Two record highs
(PHL/ACY) were tied on Tuesday, as well as a record warmest low
set at the AC Marina. Here`s a rundown of record warmest high
and low temperatures for today.

Record Warmest High Temperatures
Site                Wednesday 7/30
AC Marina (55N)       99 in 2002
AC Airport (ACY)      96 in 2002
Allentown (ABE)       97 in 1940
Georgetown (GED)      99 in 1949
Mount Pocono (MPO)    90 in 1954
Philadelphia (PHL)    98 in 1988
Reading (RDG)         97 in 1940
Trenton (TTN)         98 in 1999
Wilmington (ILG)      97 in 1954

Record Warmest Low Temperatures
Site                Wednesday 7/30
AC Marina (55N)       79 in 2020
AC Airport (ACY)      76 in 2015
Allentown (ABE)       74 in 2024
Georgetown (GED)      78 in 2009
Mount Pocono (MPO)    68 in 1909
Philadelphia (PHL)    80 in 2002
Reading (RDG)         75 in 1933
Trenton (TTN)         78 in 1894
Wilmington (ILG)      75 in 2019

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Heat Advisory until 8 PM EDT this evening for PAZ054-055-
     060>062-070-071-101>106.
     Flood Watch from Thursday afternoon through late Thursday
     night for PAZ054-055-060>062-070-071-101>106.
NJ...Heat Advisory until 8 PM EDT this evening for NJZ001-007>010-
     012>015-017>020-026-027.
     Flood Watch from Thursday afternoon through late Thursday
     night for NJZ001-007>010-012>027.
DE...Heat Advisory until 8 PM EDT this evening for DEZ001.
     Flood Watch from Thursday afternoon through late Thursday
     night for DEZ001>004.
MD...Flood Watch from Thursday afternoon through late Thursday
     night for MDZ012-015-019-020.
MARINE...None.

&&

$$

SYNOPSIS...Kruzdlo
NEAR TERM...MPS
SHORT TERM...Kruzdlo
LONG TERM...Kruzdlo
AVIATION...Kruzdlo/MPS
MARINE...DeSilva/Kruzdlo/MPS
CLIMATE...PHI